Raman imaging of erythrocytes infected with the malaria parasite Plasmodium falciparum

Red blood cells infected with the malaria parasite Plasmodium falciparum have been investigated with Raman spectroscopy. Using a motorized stage and a Raman microscope, Raman spectra have been collected from a grid of points superimposed over the optical image of infected erythrocytes, with a step of 1 m. A preliminary data analysis evidenced the anomalous distribution of hemoglobin in infected cells compared to normal erythrocytes, indicating the position occupied by the parasite inside the cells. Such information, obtained without the use of any staining, has been confirmed by cluster analysis performed on the Raman data set. Spectroscopic data clearly evidenced the presence of hemozoin (or malaria pigment), the crystalline detoxification product of host hemoglobin. This indicates that Raman imaging can provide useful informations on the internal structure of parasites. These preliminary data suggest that the imaging based on “point to point” Raman mapping could be exploited to study the malaria parasite and its interaction with the red blood cells, also upon exposure to anti-malarial drugs. ANTIMAL EU018834 support is acknowledged Sara Finaurini is training AntiMal International PhD Programme